Not compatible with express serverMiddleware

When a custom serverMiddleware is added that exports an express instance, all @nuxt/content client-side requests hang rather than resolving.

Version

@nuxt/content: v1.4.1 nuxt: v2.13.3

Reproduction link

https://codesandbox.io/s/nuxtcontent-demo-x11rc

Steps to reproduce

1. Create serverMiddleware that exports an express instance that uses json middleware, for example:

   import express from 'express'
   const app = express()
   // Note that without following line this bug is not reproduced
   app.use(express.json())
   app.get('/api/test', (req, res) => res.end())
   export default app
   

2. Add it to nuxt.config.js:

   serverMiddleware: [require.resolve("./api/test.js")],
   

What is expected?

I expect adding additional endpoints as above should not interfere with the endpoint @nuxt/content adds.

What is actually happening?

All @nuxt/content client-side requests hang rather than resolving.

[NozomuIkuta]

@Atinux

Since “done is better than perfect”, I submitted a PR where Nuxt Content gets request body by an option, whose default value is 'body' (i.e. req.body), assuming body-parser is already used in the pipeline.

User can override this option so that Nuxt Content can be agnostic on what server middleware consumes read stream and which property is populated.

Please see the PR for more detail.

[NozomuIkuta]

@Atinux @danielroe

I’ve looked into this issue to have a fun on weekend.

If I understand it correctly, the root cause is that express.json() (i.e. body-parser package, or raw-body package more accurately) consumes all the stream before the req is passed to Nuxt Content’s middleware.

So, the event listeners below are never called, and consequently the promise remains pending forever:

https://github.com/nuxt/content/blob/ebaedede5935f597fe325322ef57f09f6222e1ff/packages/content/lib/middleware.js#L19-L28

This promise stuck can be avoided by adding a condition to if-block, because body-parser sets req._body as true when it populates req.body:

if (['POST', 'PUT'].includes(req.method) && !req._body) { /* ... */ }

But, this solution would not be appropriate because now Nuxt Content becomes wary about behavior of package(s) that it doesn’t depend on. Perhaps, do you think it’s fine only if we provide some guide in documentation?

By the way, there might be more information that I have not yet found, but I would stopped research here since it’s over 1:30 a.m. in Japan. I think I should go to bed for health, rather than sticking to have a fun. 🛏️ 🙏 🤣